Mounting for color-control elements in cathode-ray tubes



H. B. VINCENT 2,823,328

MOUNTING FOR COLOR-CONTROL ELEMENTS IN cATHoDE- AY TUBES Feb. 11, 1958 Filed April 20, 1956 z 0mm 5 United States Patent MOUNTING FOR COLOR-CONTROL ELEIVIENTS m CATHODE-RAY TUBES Harvard B. Vincent, Toledo, Ohio, assignor to 0wens- Illinois Glass Company,a corporation of Ohio- Application April 20, 1956, Serial No. 579,549

11 Claims. (Cl. 31364) The present invention relates to cathode-ray tubes and more specifically to cathode-ray pictures tubes for color television transmission and reception.

The development of color television pictures tubes has been hindered by the stringent requirements of preclse alignment of internal components, particularly the colorproducing elements mounted within the face plate portion of the tube. An apertured electrode structure such as a shadow mask or line grid is usually disposed adjacent to the screen to control electron impingement upon phosphors capable of producing three primary colors. The electrode structure frequently consists of a heavy frame and bulky clamping mechanism, both of which add to the difliculty of tube assembly and exhaust. The location of the apertured electrode must be carefully controlled with respect to the phosphor screen in each individual tube for proper color registry.

An object of this invention is-to provide an improved supporting structure within a cathode-ray tube envelope for an electron beam deflecting element for directing and accelerating the electrons of the beam onto respective color areas of the tube screen.

Another object of this invention is to provide improved support means for a color-control element within the face plate portion of a cathode-ray tube envelope which support means are radially disposed about the interior of the face plate.

Another object of this invention is to provide a structure for mounting a color-control element in a cathoderay tube which structure is readily adaptable to incorporation into a conveniently shaped glass face plate.

Another object of this invention is to provide a plurality of support members which are adherent to the inner surfaces of a glass face plate for the detachable retention of a color-control element therebetween in a reproducible and reusable aligned position.

Another object of this invention is to furnish an improved face plate for a color-producing cathode-ray tube envelope having a plurality of support members of simple construction attached to its interior with a design applicable to existing and proposed types of picture tubes.

The specific nature of this invention, as well as other objects and advantages thereof, will become apparent to those skilled in the art from the following detailed description taken in conjunction with the annexed sheet of drawing, on which by way of preferred example only, is shown one embodiment of this invention.

On the accompanying drawing:

Fig. 1 is a vertical sectional view of the viewing porticn of a cathode-ray tube envelope.

Fig. 2 is an enlarged vertical sectional view of the support assembly shown on the left side of Fig. 1.

Fig. 3 is a further enlarged sectional view taken along the line 33 of Fig. 2.

Fig. 4 is a plan view of a support member only shown attached to the face plate in Figs. 1, 2, and 3.

A cathode-ray tube envelope, as designated in Fig. l by the numeral 10, generally consists of a frusto-conical shaped funnel 11. and faceplate 12 which are sealed together to constitute the major part of the tube body. The face plate 12 has a uniformly curved viewing window 13 in its central portion which-is surrounded. by an annular flange 14 extending. from the periphery of its concave surface. The flange 14 terminates at a sealing surface which is joined to the large end of matching contourand dimensions of the funnel 11 along the line 15. The line 11a refers to a change in curvature of funnel 11 wherefrom a short flange extends terminating at. the sealing line 15. The face plate 12 is composed; of glass, and is usually either round or rectangular in shape.

Two or more clip members 18 which serve as rigid supports are disposed along the length of the inner surface of flange 14 in spaced relationship. Each of the clip members 18 has a plurality of perforations. or openings 19 extending transversely through its central portion which are placed contiguous with the flange 14. Each member 18 consists ofan L-shaped structure fabricated of metal with especially formed ends for retaining a colorcontrol structure 16 withintheface plate 12. The colorcontrol structure 16 is retained by a plurality of support arms 24 and 25' attached to its periphery which engage the clip members 18.

The ends of clip member 18 are prepared with two distinctively shaped contours facing each: other generally perpendicular to its longitudinal axis. One end of clip member 18 is shaped into a coextensive shallow U-shaped notch 21 and the other is formed into a double thickness ledge from a central portion 20 bent outward at substantially a right angle into contact with the end portion 22. Thus the contacting portions 20' and 22 jointly form the shorter leg of the L-shaped structure. A threaded bolt 23 with a rounded head facing inwardly toward the notch 21 isinserted into an internally threaded bushing 17 in an opening 18b formed in, the center of the doubly thick ledge composed of contacting portions 20 and 22 as shown in Figs. 2, 3, and 4.

In one embodiment'of this invention each clip member 18 which contacts the glass is made from metal matching the expansion and contraction properties of the glass. The clip members 18 are directly attached to the glass of flange 14' by fusion when a portion of the glass in prescribed locations is heat-softened and members 18 are pressed therein as inFig; 2. The softened glass of flange 14 moves into and through the openings 19 of each clip member 18. The glass adheres to the sides of the openings 19 and to the outer surface 18a of the clip member 18 to considerably increase its surface adhesion area. It is preferable that at least three clip members 18 be mounted at spaced intervals within the flange 14 of a round; or rectangular face plate 12. Only two such members 18 are illustrated in Fig. 1.

In another application of'this invention the individual clip members 18 are coated with a low-melting glass, sealing composition 26 on their sealing areas and attached to the flange 14 as shown in Fig. 5. The sealing composition 26 is coated over the surface 18a and over the inner walls of openings 19 of each clip member 18 prior to its installation within the flange 14. Thus the sealing, composition 26 extends into the openings 19 and over the outer surface 18a of the longer leg of each clip member 18. The sealing composition 26 has uniting properties compatible with both the metal of clip member 18" and the glass of flange 14 between which it is interposed. An example of such asealing composition is one which has. a fiber softening point in the range of 450 to 500 C. and is sufiiciently chemically durable to resist devitr-ification. The sealing composition-26 also has thermal properties which permit its being heat-softened at tern.- peratures below which deformation or objectionable stresses are created in the glass flange 14.

Either the glass of flange '14 or the sealing composition 26 is able to contact a greater surface area of clip member 18 to increase its adhesion to the flange 14. This increased surface adhesion area creates a firmer bond between the clip member 18 and the flange 14 than obtainable by uniting planar surfaces. The shear strength of the joined parts is greatly increased by the extensions of vitreous material extending into the openings 19 of clip members 18. The increased shear strength and surface adhesion permit fabrication of clip members 18 from a wide range of metallic materials when sealing composition 26 is used.

Attachment of the plurality of clip members 18 may also'be accomplished by glazing the interior of the flange 14 at locations where the members 18 are to be mounted with the low-melting glass sealing composition 26 compatible with both the glass and metal employed. The sealing composition 26 on flange 14 is softened by a localized application of heat and the clips 18 are placed therein so that the composition 26 extends completely through the openings 19 and therebeyond if desired to form what in effect are rivets or extensions of glass sealing composition 26. Uniting the parts thusly is also illustrated in Fig. 5.

The color-control structure 16 which consists of a shadow mask or line grid is located within the face plate 12 attached to the flange 14 by the clip members 18 as shown in Figs. 1 and 2. Twin arms 24 and 25 are firmly attached to the outer edge of the structure 16 at the same peripheral locations as the clip members 18 into which they are fitted. Ann 24 has a lengthwise V-shaped groove on its free end generally perpendicular to the tube axis which may be slipped over the head of bolt 23. Arm 25 is a longer spring-like element which has its free end inserted into the shallow notch 21 as shown in Figs. 1 and 2. With three V-shaped arms 24 fitted over three bolts 23 at spaced intervals the structure 16 is held in a single rigid position in its mounting plane. The arms 25 provide a spring loading of the arms 24 against the pins 23 and facilitate rapid removal from and reinsertion of the structure 16 in the face plate 12. The single mounting position is aligned with the tube screen located on the inner surface of the viewing window 13 for proper control and impingement of the electron beam.

The combination of clip members 18 and engaging arms 24 and 25 at three spaced locations around the face plate 12 provide rigid reusable supporting points which facilitate reproducible alignment of the structure 16 with respect to the screen on viewing window 13. Since the plurality of clip members 18 must carry the imposed load of the structure 16 with complete reliability, their attachment as described by the glass alone or by a glass-like sealing composition 26 is exceedingly effective within a conventional glass face plate. An improvement in the shear strength of the glass-to-metal attachment has been shown to be greater by a factor of two as compared with simple planar surface-to-surface uniting.

Additional modifications may be resorted to within the spirit and scope of the appended claims.

I claim:

1. hollow glass face plate for a cathode-ray tube comprising a curved viewing portion and an annular flange portion extending around the periphery of said viewing portion, support members positioned along the inner surface of said flange, at least one opening in each support member, and vitreous material extending through said opening fusedly attaching said support member to said flange.

2. A hollow glass face plate for a cathode-ray tube comprising a curved viewing portion and an annular flange portion extending around the periphery of said viewing portion, a plurality of support members positioned along the inner surface of said flange in spaced relationship, a plurality of openings in each of said sup port members, and a portion of the glass of said flange e x 4 tending through the majority of said openings to fusedly attach said support members to said flange.

3. A hollow glass face plate for a cathode ray tube comprising a curved viewing portion and an annular flange portion extending around the periphery of said viewing portion, a plurality of L-shaped support members disposed along the inner surface of said flange in spaced relationship, a plurality of openings in each of said support members, and a portion of the glass of said flange extending through said openings to attach said support members. 1 p

4. A hollow glass face plate for a cathode-ray tube comprising a curved viewing portion and an annular flange portion extending around the periphery of said viewing portion, support members disposed along the inner surface of said flange in spaced relationship, at least one opening in each of said support members, and a lowmelting glass sealing composition fusedly interposed between said flange and support members extending into the openings of the latter.

5. A hollow glass face plate for a cathode-ray tube comprising a curved viewing window in an annular flange extending around the periphery of said viewing window, rigid support members disposed along the inner surface of said flange in spaced relationship, increased surface areas comprising a series of openings integrally formed contiguous with the central portion of each of said support members, and a joint of greater strength consisting of a low-melting glass sealing composition fusedly interposed between said flange and the openings of said increased surface areas of each of said support members for their firm attachment thereto.

6. A hollow glass face plate for a cathode-ray tube comprising a curved viewing window and annular flange extending around the periphery of said viewing window, a plurality of support members radially disposed along the inner surface of said flange in spaced relationship, a plurality of openings extending through each of said support members, a glass sealing composition interposed between said flange and said support members extending through the openings of said support members for their attachment thereto, and retention means on the inner surfaces of said support members adapted to retain an electronic element therebetween.

7. A hollow glass face plate for a cathode-ray tube comprising a curved viewing window and annular flange extending aroundthe periphery of said viewing window, at least three support members radially disposed on the inner surface of said flange in spaced relationship, a series of openings extending through each of said support members, a low-melting glass sealing composition interposed between said flange and said support members extending through and beyond the openings in said support members for their attachment to said flange, and shaped internal surfaces on said support members adapted to engageably support an electronic element within said face plate.

8. A hollow glass face plate for a cathode-ray tube comprising a curved viewing window and annular flange extending around the periphery of said viewing window, at least three support members radially disposed on the inner surface of said flange in substantially uniformly spaced relationship, a series of openings extending through each of said support members, a low-melting glass sealing composition interposed between said flange and said support members extending through and beyond the openings in said support members for their attachment to said flange, and an internal surface having a notch and pin on opposing ends of each of said support members for retaining spring loading devices on an electronic element supported within said face plate.

9. A hollow glass face plate for a cathode-ray tube comprising a curved viewing window and annular flange extending around the periphery of said viewing window, three support members radially disposed on the inner surface of said flange in substantially uniformly spaced relationship, a series of openings extending through each of said support members, a low-melting glass sealing composition interposed between said flange and said support members extending through and beyond the openings in said support members for their attachment to said flange, internally shaped surfaces on each of said support members consisting of a notch and pin on opposing ends thereof, and an electron-controlling element detachably mounted upon said internally shaped surfaces of said support members.

10. A support member for retaining an electronic element Within a cathode-ray tube envelope comprising an L-shaped structure, a plurality of openings in the central portion thereof, and a coating of low-melting glass sealing composition placed contiguous with said openings on the outer surface of said structure to fusedly attach said member to said tube envelope.

11. A support member for retaining an electronic element within a cathode-ray tube envelope comprising an L-shaped structure, pin and notch portions on opposite ends of said structure facing one another, a plurality of openings extending transversely through the longer leg portion of said structure, and a coating of low-melting glass sealing composition placed along the outer surface of said longer leg portion extending through said openings to fusedly attach said member to said tube envelope.

References Cited in the file of this patent UNITED STATES PATENTS 2,546,828 Levy Mar. 27, 1951 2,733,366 Grimm Jan. 31, 1956 2,736,832 Zaphiropohlos Feb. 28, 1956 2,755,405 Wilhelm July 17, 1956 

